Calderon’s announcement comes on the heels of his knockout loss to Moises Fuentes, which was a bid to regain the WBO 105-pound title Calderon held from 2003 until 2007.

Calderon (35-3-1, 6 KO), who represented his native Puerto Rico at the 2000 Olympics in Sydney, exits the sport as one of the most accomplished champions in boxing’s smaller weight classes. During his first reign, Calderon made 11 mostly dominant defenses of his WBO strawweight title.

So sublime were Calderon’s boxing skills that they completely offset his lack of power and justified his prominent place on several major Top Rank undercards. Based on technique and ability, Calderon was certainly worthy of being a major headliner, but the sad reality is that boxing’s smallest weight classes don’t garner much mainstream attention.

Still, Calderon forged a remarkable championship career, and he was successful even when he vacated his strawweight title in 2007 to test himself at light flyweight. At that new weight division, Calderon also captured the WBO title, defending his strap six times to become an established champion in two weight divisions.

One of the most revered traits in boxing is a fighter’s ability to claim world titles in multiple divisions. Despite boxing’s 17 weight classes, it is somewhat rare for fighters to have genuinely established championship reigns in more than one division.

Calderon is one of the few who did.

Despite the fact that he is retiring, Rafael reports that Calderon will remain active in boxing:

Calderon, a 2000 Puerto Rican Olympian, made the [retirement] announcement at the Amelia Municipal Boxing Gym in his hometown of Guaynabo, Puerto Rico. Calderon plans to work as trainer and administrator at the gym.

“This was difficult because (boxing is) something I love, but I want to say that I'm doing this not because I'm old or tired. I'm doing this because I want to work with the kids and youth, bringing them my knowledge and tips,” Calderon said at a ceremony attended by his family, trainers Jose “Cheche” Sanchez and Felix Pagan Pintor, Guaynabo mayor Hector O'Neill, WBO president Francisco “Paco” Valcarcel and several top Puerto Rican fighters, including junior lightweight titlist Roman “Rocky” Martinez and former titleholders Juan Manuel Lopez and Wilfredo Vazquez Jr.

“I want to be an example for all my fellow boxers that when it is time (to retire) it is time, no matter if we are rich or poor. The health is what matters. I want to thank all (the fans).”

That Calderon will remain involved in the sport is a blessing for future generations of boxers. During his incredible career, Calderon amassed an 18-2-1 record in title fights and between 2003 and 2011, he contested a remarkable 21 consecutive championship bouts.

As is so often the case with elite boxers, time eventually caught up with Calderon, and his last three championship fights ended in defeat.

Calderon's first loss came via an eighth-round knockout by Giovani Segura in an excellent 108-pound unification fight. Though he was stopped for the first time in his career, Calderon, in true championship fashion, sought redemption.

In the subsequent rematch, however, Calderon would lose—this time via a third-round knockout—and despite his bravery, it was evident that Calderon was no longer the slick mover and untouchable boxer of his prime years. This was confirmed when Calderon moved back down to strawweight and was stopped by Fuentes, a fighter whom Calderon in his prime likely would have boxed circles around.

Late-career setbacks aside, Calderon should be strongly considered for first-ballot induction into the Hall of Fame five years from now. Rafael points out that “during his strawweight reign, Calderon defended against the best fighters the division had to offer, including five former world titleholders: Alex "El Nene" Sanchez, Edgar Cardenas, Roberto Leyva, Daniel Reyes and Isaac Bustos.”

Coupling this with Calderon’s record in title fights and his ability to consistently score lopsided decisions against elite fighters, despite lacking power, it is clear that Calderon is a worthy Hall of Fame candidate.

Sometimes a boxer’s Hall of Fame candidacy boils down to that which cannot be easily quantified: Arturo Gatti’s courage and resilience come to mind, and Calderon's career is the kind of case that fuels intense debate.

With Calderon, however, the facts are all there.

This is not to say that either means of entering the Hall of Fame is superior. Boxing is a sport built both on numbers and illogical feats of bravery, skill and endurance. Ivan Calderon has the record to ensure that he will be remembered as an all-time great, but it is the purity of his boxing ability that should not be forgotten.